Need Information On Multicast Protocol Required By Cascade 7.X

jhh's Avatar


20 Nov, 2012 08:07 PM

For upgrade purposes I need infomrnation about the multicast level required by Cascade server 7.x.

A quick search through the knowledge base says little about multicast dependencies.

John Hayes

  1. 1 Posted by Ryan Griffith on 20 Nov, 2012 08:45 PM

    Ryan Griffith's Avatar

    Hi John,

    The multicast level in Cascade 7.x is set at 32.

    A sample configuration can be found at the bottom of the ehcache.xml configuration file that is located in tomcat/conf. The level is indicated by the timeToLive parameter.

            properties="peerDiscovery=automatic, multicastGroupAddress=,
            multicastGroupPort=4446, timeToLive=32"/>

    Additional information about the timeToLive parameter can be found here.

    Please let us know if you have any questions.


  2. 2 Posted by jhh on 20 Nov, 2012 09:13 PM

    jhh's Avatar

    The multicast level is not the same as the TTL.
    I have additional comments to folllow this description of multicast.

    Multicast level refers to the following:

    Level 0:

    is the no support for IP Multicasting level. Lots of hosts and routers in the Internet are in this state, as multicast support is not mandatory in IPv4 (it is, however, in IPv6). Not too much explanation is needed here: hosts in this level can neither send nor receive multicast packets. They must ignore the ones sent by other multicast capable hosts.

    Level 1:

    is the support for sending but not receiving multicast IP datagrams level. Thus, note that it is not necessary to join a multicast group to be able to send datagrams to it. Very few additions are needed in the IP module to make a Level 0 host Level 1-compliant.

    Level 2:

    is the full support for IP multicasting level. Level 2 hosts must be able to both send and receive multicast traffic. They must know the way to join and leave multicast groups and to propagate this information to multicast routers. Thus, they must include an Internet Group Management Protocol (IGMP) implementation in their TCP/IP stack.

    Multicasting and linux

    Linux is, full Level-2 Multicast-Compliant. It meets all requirements to send, receive and act as a router (mrouted) for multicast datagrams. Once the kernel is configured and installed, you should provide a default route for multicast traffic. The goal is to add a route to the network
    route add netmask dev eth0

    Based on the description of the dependency of 7.x for multicast to support cache synchronization the network to do support this functionality MUST be pier to pier which would absolutely require level 2 multicasting.

    This became a question of concern with our network folks as they regulate things like multicast levels and they wanted to know.

    If you any contrary information let me know.

    John Hayes

  3. 3 Posted by Ryan Griffith on 20 Nov, 2012 09:34 PM

    Ryan Griffith's Avatar

    Hi John,

    My apologies for the misunderstanding.

    You are correct, Level 2 would be required because traffic is both sent and received.

    Please let us know if you have any additional questions.


  4. Ryan Griffith closed this discussion on 11 Jan, 2013 01:24 PM.

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